fix: update djot query for upstream changes

Author: stevearc

queries/djot/aerial.scm

@@ -1,16 +1,4 @@
 (section
-  [
-    (heading1
-      (content) @name)
-    (heading2
-      (content) @name)
-    (heading3
-      (content) @name)
-    (heading4
-      (content) @name)
-    (heading5
-      (content) @name)
-    (heading6
-      (content) @name)
-  ]
+  (heading
+    content: (content) @name)
   (#set! "kind" "Interface")) @symbol